Progressive lip numbness due to numb chin and cheek syndrome in a patient with prostate cancer

Numb chin syndrome (NCS) is characterized by numbness in an area of the chin and lower lip along the distribution of the mental or inferior alveolar nerves, a branch of the mandibular division of the trigeminal nerve. Most cases of NCS are due to diffuse metastatic disease, especially associated with underlying lymphoproliferative and breast cancer. Other less like causes are dental, traumatic, toxic, drug-induced, or infectious. NCS may be the initial symptom of malignancy or metastasis in patients with cancer. Axial and vertebral bone metastases are common in patients with carcinoma of the prostate; however, involvement of the branches of the trigeminal nerve is rare. We present a case of the NCS in a 59-year-old man with metastatic prostate adenocarcinoma to the base of the skull.